The present invention relates to fluidically coupling fluidic components, in particular in a high performance liquid chromatography application.
In liquid chromatography, a fluidic sample (mobile phase) may be pumped through conduits and a column comprising a material (stationary phase) which is capable of separating different components of the fluidic analyte. Such a material, so-called beads which may comprise silica gel, may be filled into a column tube which may be connected to other elements (like a sampling unit, a flow cell, containers including sample and/or buffers) by conduits.
The flow path of the mobile phase typically comprises plural individual components coupled together, which, in turn, might also be comprised of individual sub-components. Due to the high pressure applied in most HPLC application, pressure sealing of the components in and along the flow path is required. Further, in case of requirement of biocompatibility, it has to be ensured that all surfaces of components (including conduits) along the flow path, which may come in contact with the mobile phase and the sample fluid, are comprised of materials generally considered as being biocompatible, i.e. not to release ions (e.g. from metal parts) which may contaminate the sample and/or a column packaging material, and/or adversely affect the analysis itself. Accordingly, proper sealing is required to ensure such biocompatibility. Sealings should also provide for a small dead volume and low carryover.
A so called fitting is a fluidic component being capable of providing a sealed connection between a capillary and another fluidic conduit (such as another capillary or a channel in a substrate or the like).
U.S. Pat. No. 3,973,792 discloses that, in a connecting device for connecting chromatographic separating columns of glass to terminal fittings on a chromatographic apparatus, each end of the column is surrounded by a metallic sleeve. A sleeve made of synthetic plastic material, which is of substantially stable shape at least up to a temperature of 350° centigrade even if subjected to pressure, is interposed between said end and said metallic sleeve. The plastic sleeve has at least one conical end face and is held in sealing engagement with the end of the separating column, on one hand, and with the metallic sleeve, on the other hand, by a sleeve shaped thrust member, which is axially movable relative to the metallic sleeve to exert an axial force on said plastic sleeve. A radial sealing force is exerted on the synthetic plastic sleeve through its conical end face by an abutting complementary conical surface. Connecting means for gas-tightly and detachably connecting the ends of the column to the terminal fittings of the apparatus are provided on the metallic sleeve.
WO 92/15426 discloses an apparatus and a method for connecting the end of a tubular body, particularly a chromatographic capillary tube, to a detection or injection device fitting. WO 92/15426 provides an apparatus which comprises a holder having a ferrule for holding the tubular body. Connection of the tubular body to a device fitting is aided by an insertion assembly. The insertion assembly is adapted to contain the holder and force the ferrule into a seated relation with the device.
However, the requirements regarding sealing performance and mechanical stability of a fluidic component of fluidic measurement devices increases with further increasing operation pressure values. At the same time, fast and easy handling of such a fitting by a user is required.